Learn Hardcore Portuguese (Brazil): Meu plano detalhado para amanhã inclui estudar, ir ao teatro e descansar. - My detailed plan for tomorrow includes studying, going to the theater, and resting.

meu plano detalhado – slightly more neutral and common in everyday speech.
o meu plano detalhado – can sound a bit more emphatic or formal, like “the detailed plan of mine”.

In this sentence, leaving out o is natural and very typical of Brazilian Portuguese, especially in speech. You don’t have to put the article before a possessive; it’s optional and stylistic here.

Why is the adjective after the noun: plano detalhado instead of detalhado plano?

The default word order in Portuguese is noun + adjective, so plano detalhado is the normal, unmarked form.

plano detalhado = “detailed plan” (neutral)
detalhado plano would sound unusual or poetic and is not the standard way to say it.

In everyday language, you should generally place adjectives after the noun unless you have a specific stylistic or idiomatic reason not to.

Could I say meu plano detalhado de amanhã instead of para amanhã? What’s the difference?

You can say meu plano detalhado de amanhã, but it changes the nuance:

para amanhã – “for tomorrow”, focusing on the purpose/time frame (a plan that is intended for tomorrow).
de amanhã – “of tomorrow”, focusing on belonging or association with tomorrow (the plan of tomorrow).

Both are understandable, but para amanhã is more natural when you mean “my detailed plan for tomorrow” in the sense of schedule/agenda.

Why is para used here and not por? What’s the difference between para amanhã and por amanhã?

In this context, para is the correct preposition because it indicates:

time limit / target time: para amanhã = “for tomorrow / by tomorrow”.

por amanhã is not used with this meaning. por has other uses (cause, duration, movement through a place, etc.), but not for “for tomorrow” in this sense.

So, when talking about something scheduled or planned for a specific future time, use para:
meu plano para amanhã, vou viajar para amanhã, etc.

Why is it inclui and not something like inclue? How is inclui formed?

The verb is incluir (to include). It’s a regular -ir verb with a spelling change in some forms.

For ele/ela/você (third person singular, present tense):

incluir → stem inclu-
- ending -i → inclui

So:

eu incluo
você / ele / ela inclui
nós incluímos
vocês / eles / elas incluem

inclue is incorrect spelling in modern Portuguese.

Why are the verbs estudar, ir, descansar in the infinitive and not conjugated like estudo, vou, descanso?

They are in the infinitive because they are the direct objects of the verb inclui:

inclui estudar, ir ao teatro e descansar
= “includes studying, going to the theater and resting.”

In Portuguese, when a verb is the thing that another verb “includes”, “likes”, “wants”, etc., it usually stays in the infinitive:

Ele gosta de ler. – He likes reading / to read.
Meu plano inclui estudar. – My plan includes studying.

If you said “inclui estudo, vou ao teatro e descanso”, you would be mixing a noun (estudo) and conjugated verbs (vou, descanso) in a way that doesn’t correctly express a list of planned activities under “includes”.

What does the ão and ã in amanhã mean for pronunciation? How do I say amanhã?

Amanhã has two special features:

ã – this is a nasal vowel, similar to the “an” in French “sans” or the “uhn” in English “huh” said through your nose. You don’t fully pronounce an “n” after it; the til (~) just makes the vowel nasal.
Stress: the stress is on the final syllable: a-ma-NHÃ.

A simple approximation in English would be something like “ah-ma-nyuhn”, where the last vowel is nasal and you blend the “nh” together (like the “ny” in “canyon”).

What is ir ao teatro literally, and why do we say ao instead of para o or no?

Literally:

ir = to go
ao = contraction of a + o (“to the”)
teatro = theater

So ir ao teatro = “to go to the theater”.

Why ao?

a + o teatro → ao teatro is the standard contraction for “to the theater” (movement towards a place).
para o teatro is also possible and means “(go) to the theater” as a destination. It’s fine, just slightly different style; ir ao teatro is very idiomatic.
no teatro = em + o teatro (“in/on/at the theater”), talking about being inside or at the theater, not going there.
- Estou no teatro. – I am at the theater.

So for “going to the theater” as an activity, ir ao teatro is the usual expression.

What does the ao contraction actually represent? Is this common in Portuguese?

Yes, it’s very common. ao is a contraction of:

a (preposition “to” / “at”)
o (masculine singular definite article “the”)

So:

a + o → ao
Example: vou ao médico, vou ao mercado, vou ao teatro.

Similar contractions you must know:

a + a → à (feminine singular): vou à escola (I go to the school).
de + o → do
em + o → no
para + a → pra (very common in spoken Brazilian Portuguese).

Why is there a comma before e descansar? Is that like the Oxford comma in English?

The comma in “inclui estudar, ir ao teatro e descansar” separates items in a list:

estudar
ir ao teatro
descansar

In Portuguese, the comma before the last “e” in a simple list is usually optional and often omitted, more so than in English. Many writers would prefer:

… inclui estudar, ir ao teatro e descansar. (no comma before e)

With a comma there, it’s still correct, but it’s not the typical “Oxford comma” situation with three complex items—here it’s just a straightforward list. If you want to follow the most common modern style, skip the comma before e in cases like this.

Could I use relaxar instead of descansar? What’s the difference in meaning?

Both are understandable but the nuance is:

descansar = to rest, take a break, recover energy (more general and common).
relaxar = to relax (often more about loosening up, chilling, sometimes mentally more than physically).

In a daily-plan context, descansar is the natural, default choice for “to rest”.
relaxar might sound a bit more like “to chill out / unwind” as an activity, but it’s fine if that’s what you mean.

How would this sentence change if I wanted to stress that it’s my personal plan?

You could:

Add the article for emphasis:
- O meu plano detalhado para amanhã inclui…
  → “My detailed plan for tomorrow includes…”
Add a word like pessoal:
- Meu plano pessoal e detalhado para amanhã inclui…
  → “My personal, detailed plan for tomorrow includes…”
Use stress in speech (intonation) on meu, even with the same words:
- MEU plano detalhado para amanhã inclui…

Grammatically the original sentence is already fine; these are just ways to emphasize ownership.